EP2755072A1 - Device for optical control of an imaging system - Google Patents

Device for optical control of an imaging system Download PDF

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Publication number
EP2755072A1
EP2755072A1 EP13196049.4A EP13196049A EP2755072A1 EP 2755072 A1 EP2755072 A1 EP 2755072A1 EP 13196049 A EP13196049 A EP 13196049A EP 2755072 A1 EP2755072 A1 EP 2755072A1
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EP
European Patent Office
Prior art keywords
optical
control
image
imaging system
mirror
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Granted
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EP13196049.4A
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German (de)
French (fr)
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EP2755072B1 (en
Inventor
Jean-François Blanc
Kamel Houairi
Stéphane GARIN
Marc Bernot
Arnaud Liotard
Christophe Devilliers
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Thales SA
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Thales SA
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N17/00—Diagnosis, testing or measuring for television systems or their details
    • H04N17/002—Diagnosis, testing or measuring for television systems or their details for television cameras
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/005—Testing of reflective surfaces, e.g. mirrors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G01M11/0221—Testing optical properties by determining the optical axis or position of lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/62—Optical apparatus specially adapted for adjusting optical elements during the assembly of optical systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/003—Alignment of optical elements

Definitions

  • the invention relates to optical imaging systems and in particular to high resolution optical imaging systems. More specifically, the invention relates to an optical control device for these optical imaging systems.
  • an optical imaging system must have good optical quality, for example in terms of the quality of the wave surface and the stability of the line of sight.
  • an imaging system exhibits good wave-surface quality
  • a point on the scene forms an image point in the image plane having a light intensity distribution having a dimension essentially limited by the intrinsic resolution of the imaging system.
  • imaging diffiffraction limit
  • Any defect or improper positioning of the optical surfaces that make up the imaging system involves a wave surface defect that results in an increase in the size of the image point and a decrease in the resolution of the system.
  • a system initially correctly adjusted may have a drift in the quality of its wave surface as it operates.
  • One method for measuring the wave surface is to frequently acquire calibration images in order to follow the evolution of the wave surface. These calibration images can be obtained for example by taking specific shots on specific external scenes: dedicated ground sites, stars.
  • Another known solution is to provide the instrument with a self-calibration system comprising a movable head mirror which, for calibration, is oriented towards an internal target.
  • These solutions have the disadvantage of requiring specific programming of the satellite which can be at a high rate, for example every 20 minutes, each measurement requiring a shutdown of the satellite nominal programming and possibly a displacement of moving parts.
  • the acquisition of calibration images leads to strong operational constraints.
  • an optical imaging system must have good line of sight stability. This stability is to be considered at the integration time scale to avoid the "blur of images" during the integration time and in the longer term to accurately restore the location of the scenes observed.
  • IFOV Anglo-Saxon acronym for Instantaneous Field of View
  • the most important instabilities are of vibratory origin; they dimension the mico-vibratory stability performance of the platform.
  • Other instabilities are of thermo-elastic origin, they dimension the performance of thermo-elastic stability of the imager.
  • the object of the present invention is to overcome the aforementioned drawbacks.
  • the detection element of the optical control device comprises a sensor disposed at the periphery of the image detector.
  • the detection element comprises an image detector.
  • the optical system comprises a telescope comprising at least a first aspherical collector mirror and a second mirror.
  • the optical system comprises a telescope of "TMA" type for Three Mirror Anastigmat.
  • the element is arranged around the second mirror
  • the element is disposed at a distance close to the first mirror so as to minimize the effect of decreasing the useful diameter of said entrance pupil.
  • the source of the device comprises a first optical fiber arranged in a first plane perpendicular to the optical axis and a second optical fiber arranged in a second plane parallel to the first plane and offset with respect to this first plane, the first and second planes being disposed in the vicinity of the focal plane, the two defocused control images for determining a sign of the optical aberration of the imaging system.
  • the senor is a phase diversity sensor.
  • the senor performs a first calibration measurement of the control image when the imaging system presents a quality determined optical and at least a second measurement of the control image performed after a period of operation of the imaging system, the analysis means being adapted to identify an optical defect by comparison between the first and second measurement of the image control.
  • the device is adapted to identify a defocusing of the imaging system.
  • the device is adapted to identify a misalignment of a line of sight of the imaging system.
  • an optical imaging system comprising an optical control device as described above.
  • an active imaging optical system comprising an optical control device as described above.
  • the imaging system is active and further comprises control means adapted to control an actuator adapted to perform a modification of the imaging optical system so as to at least partially correct the defect.
  • the defect comprises a defocusing and the actuator is able to control a displacement of an optical element so as to correct the defocusing.
  • the defect comprises a misalignment of a line of sight and further comprising control means adapted to control a mirror-type actuator movable in rotation so as to angularly modify the line of sight to correct the misalignment.
  • the figure 1 describes a mirror M in autocollimation with respect to a convergent optical system L of focal plane Pf and focal length f.
  • the image of an emissive point S disposed in the focal plane Pf formed by the optics L and reflected by the mirror M is disposed at S ', also in the focal plane and symmetrically at the point O, which is the point at which the optical axis intersects the focal plane.
  • the figure 2 illustrates the case in which the mirror M is inclined with respect to the autocollimation position.
  • the image S 'of S is always in the focal plane but at a distance of O function of the inclination of the mirror M.
  • the figure 3 schematically illustrates a device 1 according to the invention.
  • the device 1 performs an optical control of an imaging system 101.
  • the imaging system 101 has an optical axis z and an entrance pupil.
  • the imaging system 101 is able to form an image of a scene substantially at infinity in its focal plane Pf, according to an operation referred to as the "infinity / focus" mode.
  • At least one image detector D is arranged in the focal plane Pf to detect the image of the observed scene.
  • An image detector D is for example a strip or a matrix of pixels.
  • the imaging system is a very high resolution system. In operation, the image detector D receives light rays from all points of the scene.
  • the optical control device comprises a source S light emitting and quasi-point disposed in the focal plane Pf, and the periphery of the image detector D.
  • the source S is close enough to the detector D so that part of the light rays emitted pass through the optical imaging system in the opposite direction of the light rays coming from the scene.
  • the surface control device also comprises a reflecting element 10 having a flat surface.
  • the flat surface is of medium optical quality, typically ⁇ / 20 ( ⁇ wavelength of the light wave used).
  • the element 10 is disposed upstream of the imaging system 101 by considering the propagation direction of the light rays coming from the scene.
  • the rays coming from the source S arranged in the focal plane and having passed through the system 101 form a plane wave which is reflected by the element 10.
  • the element 10 is arranged in a position and an inclination with respect to the optical axis z such that a control image 11 of the source S made by the optical system 101 and reflected by the element 10 is arranged in the plane focal point Pf on a detection element C connected to control image analysis means 11.
  • the inclination is very small and depends on the optical combination of the imaging system and its focal length.
  • the reflective element 10 in combination with the imaging system 101, produces an image of the source S on the detection element C, according to a control image 11.
  • An analysis of the control image 11 allows the identification of possible optical defects. Indeed, the rays which form the control image 11 have crossed the optical system 101 twice and the control image has defects similar to those of the image by the optical system 101 from one point of the scene to the other. 'Infinity on the image detector D.
  • the optical wave control is performed using the control image 11, "witness" of the quality of the system.
  • the element 10 has an annular shape such as to let light rays coming from the scene pass through the entrance pupil of the optical system 101.
  • the element 10 has an annular shape such that it does not completely close, and preferably it closes a minimum the optical path of the rays from the scene and entering the entrance pupil to form the image on the D. image detector
  • the ring-shaped annular shape comprises a small diameter or internal diameter Dint and a large diameter or external diameter Dext.
  • the detection element C is disposed at the periphery of the image detector D.
  • An advantage of the device according to this variant consists in the fact that the optical quality of the optical system 101 is controlled without disturbing the operation of the system, the source S, the detection element C and the reflecting element being configured to generate an image control by closing a minimum, preferably not at all, the optical path followed by the light rays from the scene.
  • This variant does not require specific programming of the system for a stop of its operation. The measurement can thus be carried out according to a very long exposure time, and therefore with a very low signal / noise ratio, which allows good measurement accuracy and a wide choice of C-sensor.
  • a special case illustrated figure 4 corresponds to the annular reflective element 10 arranged in autocollimation.
  • the detection element C is then positioned symmetrically at S with respect to the optical axis z.
  • One advantage is a simplified setting of the device 1 integrated in the imaging system 101.
  • the detection element is constituted by an image detector D.
  • the advantage is that there is no additional element disposed in the focal plane.
  • the control can be carried out without taking an image or while taking an image.
  • the source S is deactivated during the acquisitions by the detector D.
  • the second case it is allowed to add the control task to the acquired image.
  • This second case is particularly suitable for an optical control consisting of the identification of a misalignment of the target line.
  • the annular shape is continuous.
  • the annular shape consists of at least two parts symmetrical with respect to the optical axis.
  • the imaging system is a telescope comprising at least a first aspherical collector mirror M1 and a second mirror M2.
  • the telescope is of the Three Mirror Anastigmat type according to the acronym TMA, preferably a TMA telescope of the Korsch type.
  • TMA Three Mirror Anastigmat
  • the entrance pupil is disposed on the first mirror M1.
  • the telescope is of the Cassegrain type. These telescopes are for example on board satellites to observe the Earth.
  • the figure 6 schematically illustrates a Korsch type on-board telescope according to the state of the art.
  • Two light rays 21 and 22 from the observed scene located at infinity are collected by the first aspherical mirror M1 which concentrates the rays on a second mirror M2.
  • the mirror M1 has a dimension of 1 to 4 m.
  • the second mirror M2 focuses the rays into an intermediate focal plane.
  • a mirror M3 out of axis image the focal plane intermediate to the image focal plane in which are arranged the image sensors D.
  • the focal length of the assembly is long, typically 15 to 70 m.
  • Mirrors of references R fold the rays.
  • the distance M1 M2 is typically equal to 1 to 3 times the diameter of the first mirror M1.
  • a first preferred embodiment illustrated on the figure 7 comprises an annular reflective element 10 disposed around the second mirror M2 of diameter D (M2).
  • the ring has a small diameter Dint substantially equal diameter of the mirror M2 D (M2) to minimize the bulk.
  • the element 10 is integral with the mirror M2.
  • the external diameter Dext is optimized to limit the central obturation of the telescope while achieving the desired accuracy of the control device. The smaller the width of the ring, the more the control spot is resolved but the less flux is received by the sensing element.
  • An example of sizing for a mirror M2 of 300 mm is a ring of 10mm to 20mm is typically an outside diameter Dext of the order respectively of Dint + 5% to Dint + 15%.
  • the optical path followed by the rays emitted by the source S is: S / M2 / M1 / element 10 / M1 / M2 / S.
  • the inclination of the reflecting element is variable according to the relative position of the source S and the sensor C on either side of the optical axis z. For a telescope of 1 ° field, it can vary from 0 ° to 1 °.
  • An advantage of the first embodiment in which the element 10 is arranged around M2 consists in the fact that it is able to be an integral part of the mirror M2. Another advantage is that the element 10 is stable, little influenced by the evolution of the internal heat flow to the cavity formed by M1 / M2.
  • the figure 9 illustrates the dependence between the image made by an annular pupil and the image made full pupil, for the same optics convergent focal length f equal to 30 m.
  • the curve 91 corresponds to the diffraction spot 911 obtained from a full pupil with a diameter of 1.5 m
  • the curve 92 corresponds to the diffraction spot 912 corresponding to an annular pupil whose width of the ring is equal to 2 % of the pupil diameter.
  • the mid-height width of the Airy 912 task (ring) is close to the mid-height width of the Airy 911 task (full pupil).
  • This property of the annular pupils is used to perform a fine optical control of the deformation of the task in order to follow and correct the evolution of the focus. In another example, this property realizes a control of the displacement of the task in order to follow and correct the evolution of the line of sight. In a variant, the two types of evolution are simultaneously controlled.
  • the finer the annular reflective element 10 the smaller the diameter of the Airy spot, which allows a better sensitivity of the device.
  • a thin ring reflects a smaller amount of flux, and the sensitivity of the detector needs to be adapted accordingly.
  • the dimensions of the inner and outer diameters Dint and Dext of the ring 10 result from a compromise between space constraints, desired resolution and sensitivity of the detector.
  • the source S must be point or quasi-point.
  • the source comprises at least one optical fiber, which has a small footprint and allows a large choice of emission wavelength.
  • an optical fiber has an emissive dimension of 5 ⁇ m to 100 ⁇ m.
  • the system comprises two optical fibers close to one another slightly defocused, that is to say positioned in the vicinity but not exactly in the focal plane Pf, a first fiber being disposed in a first plane perpendicular to the optical axis and a second fiber in a second plane parallel to the first plane and offset with respect to this first plane, making it possible to create two defocused control images, the joint analysis of which makes it possible to determine a sign of the optical aberration of the optical system. imaging.
  • the imaging system is in operation when the wave surface control is operated with the device according to the invention.
  • This variant requires a detection element C different from the image detector D and disposed at the periphery thereof.
  • the source must not increase the level of stray light in the optical imaging system 101.
  • the imaging system 101 operates for the wavelengths in the visible light and the source S emits in the different wavelengths. , to which the detector D is less sensitive, to minimize the stray light introduced into the system 101.
  • the observation made by the imaging system 101 is stopped while the control of the wave surface is operated by the device according to the invention.
  • This variant is compatible with a detection element merged with one of the image detector D.
  • the sensor C must be able to detect the light distribution of the control image 11.
  • the sensor C may be a matrix detector, a four-dial detector, a linear sensor, a phase diversity sensor.
  • the type of sensor depends on the type of fault you want to control.
  • a control method is based on a comparison between a first measurement of the control image 11 called calibration measurement, performed when the imaging system 101 has a determined optical quality and found satisfactory, and at least a second measurement of the control image 11 made after a period of operation of the system.
  • the system is in operation when the second measurement is performed.
  • the system is momentarily stopped when the second measurement is made.
  • a first example of a type of defect controllable by the device according to the invention is a wave surface defect such as a defocusing. From a measurement of the variation of the dimension of the control image one deduces the existence of defect at the origin of the deterioration of the quality of the wave surface. For example, a defocus defect can be detected from the first and second measurements.
  • a second example of a type of defect controllable by the device according to the invention is a misalignment of the line of sight, which induces a displacement of the position of the control image 11 in the focal plane Pf. measurement of the displacement of the control image 11 it is deduced the existence of a misalignment.
  • a misalignment can be detected from a first measurement corresponding to the aligned imaging system 101 and a second measurement corresponding to the imaging system having misalignment of the line of sight.
  • a displacement measurement of the position of the control image is compatible with the use of a four-dial detector as a detection element C.
  • an optical imaging system 101 comprising an optical control device as described above.
  • the optical imaging system 101 is for example a high resolution earth observation telescope (ground resolution 20 to 50 cm) embedded on a satellite.
  • An example of arrangement of the focal plane Pf of such a system 101 comprising a device according to the invention is represented on the figure 10 .
  • the image detector D is composed of a plurality of linear or matrix sensors D1, D2, etc.
  • a retina composed of 5 linear sensors of 6000 points of 13 ⁇ m of pitch has a length L of approximately 500 mm for a height h of about 50 mm.
  • the scrolling of the scene takes place along the x axis.
  • the source S and the detection element C of the device 1 according to the invention are arranged on either side of the optical axis z in the focal plane Pf as shown in FIG. figure 10 .
  • the imaging system 110 represented on the figure 11 is active and further comprises control means 111 able to control an actuator 112 able to effect a modification of the optical imaging system 110 so as to at least partially correct the defect identified by the analysis of one or more images of control.
  • an active imaging system 110 comprising a first mirror M1 and a second mirror M2 as described above.
  • the type of defect measured includes a defocusing and the actuator 112 is able to control a displacement of an optical element, for example the second mirror M2, so as to correct the defocusing.
  • the process may be iteratively performed in a loop, performing for each actuator displacement a measurement of the control image 11 until the control image reaches a predetermined size or is of similar size to a previously saved calibration image.
  • the imaging system 120 represented on the figure 12 is active and the defect detected by the device according to the invention comprises a misalignment of the line of sight for example by using a detection element C such a detector four dials.
  • the evolution of the line of sight results in a decentering of the control image received by the detector C.
  • the analysis means coupled to the detection element identify the amplitude and the direction of the displacement.
  • the imaging system 120 furthermore comprises control means 113 able to control a mirror-type mirror rotation actuator Mtt or Tip-Tilt mirror according to the Anglo-Saxon acronym, so as to angularly modify the line of sight in order to correct the misalignment.
  • the mobile mirror Mtt is preferably placed on the exit pupil of the imaging system.
  • the process may operate iteratively in a loop, performing for each movement of the mirror Mtt a measurement of the centering of the control image 11 until the control image is centered.
  • the bandwidth of the servo loop is to be adapted to the frequency of the disturbance that is to be corrected.
  • both types of loops are implemented in the active imaging optical system and the defect includes defocusing and misalignment of the line of sight.
  • the source S and the sensor C are common to both loops.
  • the system comprises two specialized C sensors, one for the control of the wave surface and the other for the control of the line of sight.

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Abstract

The device has a virtually point-like emission source (S) arranged on a periphery of image detector (D) and a focal plane (Pf), and a reflecting element (10) fixed upstream of an imaging system (101) by considering direction of propagation of the light rays from a scene and according to a position and inclination such that a monitoring image (11) of the source reflected by the element is placed on a detection element (C) connected to analyzing unit of the image to identify optical defects. The element is in annular shape so as to allow passage of light rays through an entry pupil. An independent claim is also included for an active optical imaging system.

Description

DOMAINE DE L'INVENTIONFIELD OF THE INVENTION

L'invention concerne les systèmes optiques d'imagerie et en particulier les systèmes optiques d'imagerie haute résolution. Plus précisément, l'invention concerne un dispositif de contrôle optique de ces systèmes optiques d'imagerie.The invention relates to optical imaging systems and in particular to high resolution optical imaging systems. More specifically, the invention relates to an optical control device for these optical imaging systems.

ETAT DE LA TECHNIQUESTATE OF THE ART

Pour fonctionner de manière satisfaisante, un système optique d'imagerie doit présenter une bonne qualité optique, par exemple au niveau de la qualité de surface d'onde et de la stabilité de l'axe de visée.
Lorsqu'un système d'imagerie présente une bonne qualité de surface d'onde, un point de la scène forme dans le plan image un point image présentant une répartition d'intensité lumineuse présentant une dimension essentiellement limitée par la résolution intrinsèque du système d'imagerie (limite de diffraction). Tout défaut ou mauvais positionnement des surfaces optiques qui composent le système d'imagerie implique un défaut de surface d'onde qui se traduit par une augmentation de la dimension du point image et une diminution de la résolution du système.
De manière générale, un système initialement correctement réglé peut présenter une dérive de la qualité de sa surface d'onde au fur et à mesure de son fonctionnement.
Pour des systèmes d'imagerie embarqués sur des satellites pour observer la terre, tels des instruments comme des télescopes à haute résolution, un suivi de l'évolution de la surface d'onde est nécessaire pour garantir la qualité des images enregistrées.
Une méthode pour mesurer la surface d'onde est d'acquérir fréquemment des images de calibration afin de suivre l'évolution de la surface d'onde. Ces images de calibration peuvent être obtenues par exemple en réalisant des prises de vue spécifiques sur de scènes externes spécifiques : sites sol dédiés, étoiles.To function satisfactorily, an optical imaging system must have good optical quality, for example in terms of the quality of the wave surface and the stability of the line of sight.
When an imaging system exhibits good wave-surface quality, a point on the scene forms an image point in the image plane having a light intensity distribution having a dimension essentially limited by the intrinsic resolution of the imaging system. imaging (diffraction limit). Any defect or improper positioning of the optical surfaces that make up the imaging system involves a wave surface defect that results in an increase in the size of the image point and a decrease in the resolution of the system.
In general, a system initially correctly adjusted may have a drift in the quality of its wave surface as it operates.
For imaging systems embedded on satellites to observe the earth, such as instruments such as high-resolution telescopes, monitoring the evolution of the wave surface is necessary to ensure the quality of the recorded images.
One method for measuring the wave surface is to frequently acquire calibration images in order to follow the evolution of the wave surface. These calibration images can be obtained for example by taking specific shots on specific external scenes: dedicated ground sites, stars.

Une autre solution connue est de munir l'instrument d'un système d'auto-calibration comprenant un miroir mobile de tête qui, pour la calibration, est orienté vers une cible interne.
Ces solutions présentent l'inconvénient de nécessiter une programmation spécifique du satellite qui peut être à une cadence élevée, par exemple toutes les 20 mn, chaque mesure nécessitant un arrêt des programmations nominales du satellite et éventuellement un déplacement de pièces mobiles. Ainsi l'acquisition d'images de calibration conduit à de fortes contraintes opérationnelles.Another known solution is to provide the instrument with a self-calibration system comprising a movable head mirror which, for calibration, is oriented towards an internal target.
These solutions have the disadvantage of requiring specific programming of the satellite which can be at a high rate, for example every 20 minutes, each measurement requiring a shutdown of the satellite nominal programming and possibly a displacement of moving parts. Thus the acquisition of calibration images leads to strong operational constraints.

Par ailleurs, pour fonctionner de manière satisfaisante, un système optique d'imagerie doit présenter une bonne stabilité de ligne de visée. Cette stabilité est à considérer à l'échelle du temps d'intégration pour éviter le « flou des images » pendant le temps d'intégration et à plus long terme pour restituer avec précision la localisation des scènes observées .
Ces instabilités de la ligne de visée sont d'autant plus importante que l'IFOV (acronyme anglo-saxon de Instantaneous Field of View) est faible. Pour les instruments embarqués, les instabilités les plus importantes sont d'origine vibratoire ; elles dimensionnent la performance de stabilité mico-vibratoire de la plateforme. D'autres instabilités sont d'origine thermo-élastique, elles dimensionnent la performance de stabilité thermo-élastique de l'imageur .Moreover, to function satisfactorily, an optical imaging system must have good line of sight stability. This stability is to be considered at the integration time scale to avoid the "blur of images" during the integration time and in the longer term to accurately restore the location of the scenes observed.
These instabilities of the line of sight are all the more important as the IFOV (Anglo-Saxon acronym for Instantaneous Field of View) is weak. For embedded instruments, the most important instabilities are of vibratory origin; they dimension the mico-vibratory stability performance of the platform. Other instabilities are of thermo-elastic origin, they dimension the performance of thermo-elastic stability of the imager.

Le but de la présente invention est de remédier aux inconvénients précités.The object of the present invention is to overcome the aforementioned drawbacks.

DESCRIPTION DE L'INVENTIONDESCRIPTION OF THE INVENTION

Il est proposé, selon un aspect de l'invention, un dispositif de contrôle optique d'un système optique d'imagerie présentant un plan focal (Pf), un axe optique (z), une pupille d'entrée, le système formant une image d'une scène sensiblement à l'infini sur au moins un détecteur d'image disposé sensiblement dans le plan focal (Pf), le dispositif comprenant :

  • au moins une source émettrice quasi ponctuelle disposée en périphérie du détecteur et sensiblement dans le plan focal,
  • un élément réfléchissant et de surface plane,
  • l'élément étant disposé en amont du système d'imagerie en considérant le sens de propagation des rayons lumineux provenant de la scène, et selon une position et une inclinaison telles qu'une image de contrôle de la source réalisée par le système optique et réfléchie par l'élément soit disposée sensiblement dans le plan focal sur un élément de détection relié à des moyens d'analyse de l'image de contrôle permettant d'identifier d'éventuels défauts optiques,
  • l'élément (10) présentant une forme annulaire de manière à laisser passer des rayons lumineux issus de la scène et traversant la pupille d'entrée.
According to one aspect of the invention, there is provided an optical control device of an imaging optical system having a focal plane (Pf), an optical axis (z), an entrance pupil, the system forming a image of a scene substantially at infinity on at least one image detector disposed substantially in the focal plane (Pf), the device comprising:
  • at least one quasi-point source emitting disposed at the periphery of the detector and substantially in the focal plane,
  • a reflective element and flat surface,
  • the element being arranged upstream of the imaging system by considering the propagation direction of the light rays coming from the scene, and according to a position and an inclination such as a source control image made by the optical system and reflected by the element being disposed substantially in the focal plane on a detection element connected to means of analysis of the control image making it possible to identify any optical defects,
  • the element (10) having an annular shape so as to pass light rays from the scene and passing through the entrance pupil.

Selon un mode préféré, l'élément de détection du dispositif de contrôle optique comprend un capteur disposé en périphérie du détecteur image. Selon un autre mode de réalisation l'élément de détection comprend un détecteur image.
Avantageusement le système optique comprend un télescope comprenant au moins un premier miroir collecteur asphérique et un deuxième miroir. Selon un mode préféré le système optique comprend un télescope de type « TMA » pour Three Mirror Anastigmat.
Selon une variante, l'élément est disposé autour du deuxième miroir
Selon une autre variante, l'élément est disposé à une distance proche du premier miroir de manière à minimiser l'effet de diminution du diamètre utile de ladite pupille d'entrée.According to a preferred embodiment, the detection element of the optical control device comprises a sensor disposed at the periphery of the image detector. According to another embodiment, the detection element comprises an image detector.
Advantageously, the optical system comprises a telescope comprising at least a first aspherical collector mirror and a second mirror. According to one preferred embodiment, the optical system comprises a telescope of "TMA" type for Three Mirror Anastigmat.
According to a variant, the element is arranged around the second mirror
According to another variant, the element is disposed at a distance close to the first mirror so as to minimize the effect of decreasing the useful diameter of said entrance pupil.

Selon un mode de réalisation, la source du dispositif comprend une première fibre optique disposée dans un premier plan perpendiculaire à l'axe optique et une deuxième fibre optique disposée dans un deuxième plan parallèle au premier plan et décalé par rapport à ce premier plan, le premier et deuxième plan étant disposés au voisinage du plan focal, les deux images de contrôle défocalisées permettant de déterminer un signe de l'aberration optique du système d'imagerie.According to one embodiment, the source of the device comprises a first optical fiber arranged in a first plane perpendicular to the optical axis and a second optical fiber arranged in a second plane parallel to the first plane and offset with respect to this first plane, the first and second planes being disposed in the vicinity of the focal plane, the two defocused control images for determining a sign of the optical aberration of the imaging system.

Avantageusement, le capteur est un capteur par diversité de phase.Advantageously, the sensor is a phase diversity sensor.

Avantageusement le capteur effectue une première mesure de calibration de l'image de contrôle lorsque le système d'imagerie présente une qualité optique déterminée et au moins une deuxième mesure de l'image de contrôle réalisée après une période de fonctionnement du système d'imagerie, les moyens d'analyse étant adaptés pour identifier un défaut optique par comparaison entre les première et deuxième mesure de l'image de contrôle.Advantageously, the sensor performs a first calibration measurement of the control image when the imaging system presents a quality determined optical and at least a second measurement of the control image performed after a period of operation of the imaging system, the analysis means being adapted to identify an optical defect by comparison between the first and second measurement of the image control.

Avantageusement le dispositif est adapté pour identifier une défocalisation du système d'imagerie.Advantageously, the device is adapted to identify a defocusing of the imaging system.

Avantageusement le dispositif est adapté pour identifier un désalignement d'un axe de visée du système d'imagerie.Advantageously, the device is adapted to identify a misalignment of a line of sight of the imaging system.

Selon un autre aspect de l'invention, il est également proposé un système d'imagerie optique comprenant un dispositif de contrôle optique tel que décrit précédemment.According to another aspect of the invention, there is also provided an optical imaging system comprising an optical control device as described above.

Selon un autre aspect de l'invention, il est également proposé un système optique d'imagerie actif comprenant un dispositif de contrôle optique tel que décrit précédemment.
Avantageusement, le système d'imagerie est actif et comprend en outre des moyens de commande aptes à commander un actuateur apte à effectuer une modification du système optique d'imagerie de manière à corriger au moins partiellement le défaut.According to another aspect of the invention, there is also provided an active imaging optical system comprising an optical control device as described above.
Advantageously, the imaging system is active and further comprises control means adapted to control an actuator adapted to perform a modification of the imaging optical system so as to at least partially correct the defect.

Avantageusement , le défaut comprend une défocalisation et l'actuateur est apte à commander un déplacement d'un élément optique de manière à corriger la défocalisation.Advantageously, the defect comprises a defocusing and the actuator is able to control a displacement of an optical element so as to correct the defocusing.

Avantageusement, le défaut comprend un désalignement d'un axe de visée et comprenant en outre des moyens de commande aptes à commander un actuateur de type miroir mobile en rotation de manière à modifier angulairement l'axe de visée afin de corriger le désalignement.Advantageously, the defect comprises a misalignment of a line of sight and further comprising control means adapted to control a mirror-type actuator movable in rotation so as to angularly modify the line of sight to correct the misalignment.

D'autres caractéristiques, buts et avantages de la présente invention apparaîtront à la lecture de la description détaillée qui va suivre et en regards des dessins annexés données à titre d'exemples non limitatifs et sur lesquels :

  • la figure 1 illustre schématiquement le principe de l'autocollimation.
  • la figure 2 illustre schématiquement une configuration optique où le miroir plan est incliné par rapport à l'axe optique.
  • la figure 3 illustre schématiquement un dispositif selon l'invention.
  • la figure 4 illustre schématiquement un cas particulier du dispositif selon l'invention dans lequel l'élément réfléchissant est en autocollimation.
  • la figure 5 illustre un dispositif selon l'invention selon une variante de réalisation de l'invention.
  • la figure 6 illustre un schématiquement un système d'imagerie embarqué constitué d'un télescope de type Korsch selon l'état de la technique.
  • la figure 7 illustre un dispositif selon l'invention selon un premier mode de réalisation.
  • la figure 8 illustre un dispositif selon l'invention selon un deuxième mode de réalisation.
  • la figure 9 illustre la dépendance entre l'image correspondant à une pupille pleine et l'image correspondant à une pupille annulaire.
  • la figure 10 illustre un exemple d'arrangement du plan focal d'un système d'imagerie comprenant une pluralité de barrettes unidimensionnelles et comprenant un dispositif selon l'invention.
  • la figure 11 représente un système d'imagerie actif comprenant des moyens de commande et un actuateur apte à commander un déplacement du deuxième miroir du système d'imagerie.
  • la figure 12 représente un système d'imagerie actif comprenant des moyens de commande et un miroir mobile en rotation apte à modifier angulairement l'axe de visée du système d'imagerie.
Other features, objects and advantages of the present invention will appear on reading the detailed description which will follow and in view attached drawings given by way of non-limiting examples and in which:
  • the figure 1 schematically illustrates the principle of autocollimation.
  • the figure 2 schematically illustrates an optical configuration where the plane mirror is inclined with respect to the optical axis.
  • the figure 3 schematically illustrates a device according to the invention.
  • the figure 4 schematically illustrates a particular case of the device according to the invention wherein the reflective element is in autocollimation.
  • the figure 5 illustrates a device according to the invention according to an alternative embodiment of the invention.
  • the figure 6 schematically illustrates an onboard imaging system consisting of a Korsch-type telescope according to the state of the art.
  • the figure 7 illustrates a device according to the invention according to a first embodiment.
  • the figure 8 illustrates a device according to the invention according to a second embodiment.
  • the figure 9 illustrates the dependence between the image corresponding to a full pupil and the image corresponding to an annular pupil.
  • the figure 10 illustrates an exemplary arrangement of the focal plane of an imaging system comprising a plurality of one-dimensional arrays and comprising a device according to the invention.
  • the figure 11 represents an active imaging system comprising control means and an actuator adapted to control a displacement of the second mirror of the imaging system.
  • the figure 12 represents an active imaging system comprising control means and a mirror movable in rotation adapted to angularly change the line of sight of the imaging system.

DESCRIPTION DETAILLEE DE L'INVENTIONDETAILED DESCRIPTION OF THE INVENTION

Avant de décrire l'invention nous rappellons la notion d'autocollimation.
La figure 1 décrit un miroir M en autocollimation par rapport à un système optique convergent L de plan focal Pf et de focale f. Dans cette configuration, l'image d'un point S émissif disposé dans le plan focal Pf formée par l'optique L et réfléchie par le miroir M est disposée en S', également dans le plan focal et symétriquement au point O, qui est le point pour lequel l'axe optique coupe le plan focal.Before describing the invention we recall the notion of autocollimation.
The figure 1 describes a mirror M in autocollimation with respect to a convergent optical system L of focal plane Pf and focal length f. In this configuration, the image of an emissive point S disposed in the focal plane Pf formed by the optics L and reflected by the mirror M is disposed at S ', also in the focal plane and symmetrically at the point O, which is the point at which the optical axis intersects the focal plane.

La figure 2 illustre le cas dans lequel le miroir M est incliné par rapport à la position d'autocollimation. L'image S' de S est toujours dans le plan focal mais à une distance de O fonction de l'inclinaison du miroir M.The figure 2 illustrates the case in which the mirror M is inclined with respect to the autocollimation position. The image S 'of S is always in the focal plane but at a distance of O function of the inclination of the mirror M.

La figure 3 illustre schématiquement un dispositif 1 selon l'invention. Le dispositif 1 effectue un contrôle optique d'un système d'imagerie 101. De manière classique, le système d'imagerie 101 présente un axe optique z et une pupille d'entrée.
Le système d'imagerie 101 est apte former une image d'une scène sensiblement à l'infini dans son plan focal Pf, selon un fonctionnement dénommé mode « infini/foyer ».
Au moins un détecteur image D est disposé dans le plan focal Pf pour détecter l'image de la scène observée. Un détecteur image D est par exemple une barrette ou une matrice de pixels. Préférentiellement le système d'imagerie est un système à très haute résolution.
En fonctionnent, le détecteur image D reçoit des rayons lumineux provenant de tous les points de la scène.
Le dispositif de contrôle optique selon l'invention comprend une source S émettrice de lumière et quasi ponctuelle disposées dans le plan focal Pf, et en périphérie du détecteur image D.
La source S est suffisamment proche du détecteur D pour qu'une partie des rayons lumineux émis traversent le système optique d'imagerie en sens inverse des rayons lumineux provenant de la scène.The figure 3 schematically illustrates a device 1 according to the invention. The device 1 performs an optical control of an imaging system 101. In a conventional manner, the imaging system 101 has an optical axis z and an entrance pupil.
The imaging system 101 is able to form an image of a scene substantially at infinity in its focal plane Pf, according to an operation referred to as the "infinity / focus" mode.
At least one image detector D is arranged in the focal plane Pf to detect the image of the observed scene. An image detector D is for example a strip or a matrix of pixels. Preferably the imaging system is a very high resolution system.
In operation, the image detector D receives light rays from all points of the scene.
The optical control device according to the invention comprises a source S light emitting and quasi-point disposed in the focal plane Pf, and the periphery of the image detector D.
The source S is close enough to the detector D so that part of the light rays emitted pass through the optical imaging system in the opposite direction of the light rays coming from the scene.

Le dispositif de contrôle de surface selon l'invention comprend également un élément réfléchissant 10 présentant une surface plane. La surface plane est de qualité optique moyenne, typiquement λ/20 (λ longueur d'onde de l'onde lumineuse utilisée).The surface control device according to the invention also comprises a reflecting element 10 having a flat surface. The flat surface is of medium optical quality, typically λ / 20 (λ wavelength of the light wave used).

L'élément 10 est disposé en amont du système d'imagerie 101 en considérant le sens de propagation des rayons lumineux provenant de la scène. Ainsi les rayons issus de la source S disposée dans le plan focal et ayant traversé le système 101 forment une onde plane qui est réfléchie par l'élément 10.
L'élément 10 est disposé selon une position et une inclinaison par rapport à l'axe optique z telles qu'une image de contrôle 11 de la source S réalisée par le système optique 101 et réfléchie par l'élément 10 est disposée dans le plan focal Pf sur un élément de détection C relié à des moyens d'analyse de l'image de contrôle 11. Typiquement l'inclinaison est très faible et dépend de la combinaison optique du système d'imagerie ainsi que de sa focale.
Ainsi l'élément réfléchissant 10 réalise, en combinaison avec le système d'imagerie 101, une image de la source S sur l'élément de détection C, selon une image de contrôle 11.
Une analyse de l'image de contrôle 11 permet l'identification d'éventuels défauts optiques. En effet les rayons qui forment l'image de contrôle 11 ont traversé deux fois le système optique 101 et l'image de contrôle présente des défauts similaires à ceux de l'image par le système optique 101 d'un point de la scène à l'infini sur le détecteur image D. Le contrôle optique d'onde s'effectue à l'aide de l'image de contrôle 11, « témoin » de la qualité du système.
Plusieurs positions de l'élément 10 sont possibles, comme décrit plus loin.
Pour ne pas perturber le fonctionnement du système optique 101, l'élément 10 présente une forme annulaire telle qu'il laisse passer des rayons lumineux issus de la scène et traversant la pupille d'entrée du système optique 101. En d'autres termes, l'élément 10 a une forme annulaire telle qu'il n'obture pas complètement, et préférentiellement qu'il obture un minimum le chemin optique des rayons issus de la scène et pénétrant dans la pupille d'entrée pour former l'image sur le détecteur image D.
La forme annulaire en couronne, comprend un petit diamètre ou diamètre interne Dint et un grand diamètre ou diamètre externe Dext.
Un avantage du système est que le contrôle s'opère sans adjonction et déplacement d'une pièce mobile telle un miroir ou un cache, et sans avoir recours à un programme de dépointage spécifique pour un système d'imagerie embarqué sur un satellite, le contrôle s'effectuant sans modification des conditions de fonctionnement du système d'imagerie. Le dispositif selon l'invention est autonome.The element 10 is disposed upstream of the imaging system 101 by considering the propagation direction of the light rays coming from the scene. Thus the rays coming from the source S arranged in the focal plane and having passed through the system 101 form a plane wave which is reflected by the element 10.
The element 10 is arranged in a position and an inclination with respect to the optical axis z such that a control image 11 of the source S made by the optical system 101 and reflected by the element 10 is arranged in the plane focal point Pf on a detection element C connected to control image analysis means 11. Typically the inclination is very small and depends on the optical combination of the imaging system and its focal length.
Thus, the reflective element 10, in combination with the imaging system 101, produces an image of the source S on the detection element C, according to a control image 11.
An analysis of the control image 11 allows the identification of possible optical defects. Indeed, the rays which form the control image 11 have crossed the optical system 101 twice and the control image has defects similar to those of the image by the optical system 101 from one point of the scene to the other. 'Infinity on the image detector D. The optical wave control is performed using the control image 11, "witness" of the quality of the system.
Several positions of the element 10 are possible, as described below.
In order not to disturb the operation of the optical system 101, the element 10 has an annular shape such as to let light rays coming from the scene pass through the entrance pupil of the optical system 101. In other words, the element 10 has an annular shape such that it does not completely close, and preferably it closes a minimum the optical path of the rays from the scene and entering the entrance pupil to form the image on the D. image detector
The ring-shaped annular shape comprises a small diameter or internal diameter Dint and a large diameter or external diameter Dext.
An advantage of the system is that the control is effected without the addition and displacement of a moving part such as a mirror or a cache, and without resorting to a specific offsetting program for an on-board satellite imaging system, the control performed without modification of the operating conditions of the imaging system. The device according to the invention is autonomous.

Selon une variante, l'élément de détection C est disposé en périphérie du détecteur image D.
Un avantage du dispositif selon cette variante consiste dans le fait que la qualité optique du système optique 101 est contrôlée sans perturber le fonctionnement du système, la source S, l'élément de détection C et l'élément réfléchissant 10 étant configurés pour générer une image de contrôle en obturant un minimum, préférentiellement pas du tout, le chemin optique suivi par les rayons lumineux issus de la scène. Cette variante ne nécessite pas de programmation spécifique du système pour un arrêt de son fonctionnement. La mesure peut ainsi s'effectuer selon un temps de pose très long, et donc avec un très faible rapport signal/bruit, ce qui permet une bonne précision de mesure et un large choix de capteur C.
Un cas particulier illustré figure 4 correspond à l'élément réfléchissant annulaire 10 disposé en autocollimation. L'élément de détection C est alors positionné symétriquement à S par rapport à l'axe optique z. Un avantage consiste en un réglage simplifié du dispositif 1 intégré dans le système d'imagerie 101.According to one variant, the detection element C is disposed at the periphery of the image detector D.
An advantage of the device according to this variant consists in the fact that the optical quality of the optical system 101 is controlled without disturbing the operation of the system, the source S, the detection element C and the reflecting element being configured to generate an image control by closing a minimum, preferably not at all, the optical path followed by the light rays from the scene. This variant does not require specific programming of the system for a stop of its operation. The measurement can thus be carried out according to a very long exposure time, and therefore with a very low signal / noise ratio, which allows good measurement accuracy and a wide choice of C-sensor.
A special case illustrated figure 4 corresponds to the annular reflective element 10 arranged in autocollimation. The detection element C is then positioned symmetrically at S with respect to the optical axis z. One advantage is a simplified setting of the device 1 integrated in the imaging system 101.

Selon une autre variante illustrée sur la figure 5, l'élément de détection est constitué par un détecteur image D. L'avantage consiste en ce qu'il n'y pas d'élément additionnel disposé dans le plan focal. Le contrôle peut être réalisé hors prise d'image ou pendant la prise d'image. Dans le premier cas, la source S est désactivée pendant les acquisitions par le détecteur D. Dans le second cas, on admet d'ajouter la tâche de contrôle à l'image acquise. Ce second cas est particulièrement adapté pour un contrôle optique consistant en l'identification d'un désalignement de la ligne de visé.According to another variant illustrated on the figure 5 , the detection element is constituted by an image detector D. The advantage is that there is no additional element disposed in the focal plane. The control can be carried out without taking an image or while taking an image. In the first case, the source S is deactivated during the acquisitions by the detector D. In the second case, it is allowed to add the control task to the acquired image. This second case is particularly suitable for an optical control consisting of the identification of a misalignment of the target line.

Selon une variante préférée, la forme annulaire est continue.
Selon une autre variante également illustré figure 5, la forme annulaire est constituée d'au moins deux parties symétriques par rapport à l'axe optique. Selon une variante préférée, le système d'imagerie est un télescope comprenant au moins un premier miroir collecteur asphérique M1 et un deuxième miroir M2. Selon une variante préférée, le télescope est de type Three Mirror Anastigmat selon l'acronyme anglo-saxon TMA, préférentiellement un télescope TMA de type Korsch. Pour ces télescopes, la pupille d'entrée est disposée sur le premier miroir M1.
Selon un autre exemple le télescope est de type Cassegrain.
Ces télescopes sont par exemple embarqués à bord de satellites pour observer la Terre.
La figure 6 illustre schématiquement un télescope embarqué de type Korsch selon l'état de la technique. Deux rayons lumineux 21 et 22 issus de la scène observée située à l'infini sont collectés par le premier miroir asphérique M1 qui concentre les rayons sur un deuxième miroir M2. Par exemple le miroir M1 a une dimension de 1 à 4 m. Le deuxième miroir M2 focalise les rayons en un plan focal intermédiaire. En partie arrière, un miroir M3 hors d'axe image le plan focal intermédiaire au plan focal image dans lequel sont disposés les détecteurs image D. La focale de l'ensemble est longue, typiquement 15 à 70 m. Des miroirs de renvois R replient les rayons.
La distance M1 M2 est typiquement égale à 1 à 3 fois le diamètre du premier miroir M1.According to a preferred variant, the annular shape is continuous.
According to another variant also illustrated figure 5 , the annular shape consists of at least two parts symmetrical with respect to the optical axis. According to a preferred variant, the imaging system is a telescope comprising at least a first aspherical collector mirror M1 and a second mirror M2. According to a preferred variant, the telescope is of the Three Mirror Anastigmat type according to the acronym TMA, preferably a TMA telescope of the Korsch type. For these telescopes, the entrance pupil is disposed on the first mirror M1.
According to another example, the telescope is of the Cassegrain type.
These telescopes are for example on board satellites to observe the Earth.
The figure 6 schematically illustrates a Korsch type on-board telescope according to the state of the art. Two light rays 21 and 22 from the observed scene located at infinity are collected by the first aspherical mirror M1 which concentrates the rays on a second mirror M2. For example, the mirror M1 has a dimension of 1 to 4 m. The second mirror M2 focuses the rays into an intermediate focal plane. In the rear part, a mirror M3 out of axis image the focal plane intermediate to the image focal plane in which are arranged the image sensors D. The focal length of the assembly is long, typically 15 to 70 m. Mirrors of references R fold the rays.
The distance M1 M2 is typically equal to 1 to 3 times the diameter of the first mirror M1.

Nous allons à présent décrire à titre d'exemple deux modes de réalisation du dispositif selon l'invention pour un télescope tel que décrit précédemment.We will now describe by way of example two embodiments of the device according to the invention for a telescope as described above.

Un premier mode de réalisation préféré illustré sur la figure 7 comprend un élément réfléchissant annulaire 10 disposée autour du deuxième miroir M2 de diamètre D(M2). Préférentiellement la couronne a un petit diamètre Dint sensiblement égal diamètre du miroir M2 D(M2) pour minimiser l'encombrement. En variante, l'élément 10 est solidaire du miroir M2. Préférentiellement le diamètre externe Dext est optimisé pour limiter l'obturation centrale du télescope tout en permettant d'atteindre la précision recherchée du dispositif de contrôle. Plus la largeur de l'anneau est faible, plus la tache de contrôle est résolue mais moins il y a de flux reçu par l'élément de détection. Un exemple de dimensionnement pour un miroir M2 de 300 mm est un anneau de 10mm à 20mm soit typiquement un diamètre extérieur Dext de l'ordre respectivement de Dint + 5% à Dint +15%.A first preferred embodiment illustrated on the figure 7 comprises an annular reflective element 10 disposed around the second mirror M2 of diameter D (M2). Preferably the ring has a small diameter Dint substantially equal diameter of the mirror M2 D (M2) to minimize the bulk. Alternatively, the element 10 is integral with the mirror M2. Preferably the external diameter Dext is optimized to limit the central obturation of the telescope while achieving the desired accuracy of the control device. The smaller the width of the ring, the more the control spot is resolved but the less flux is received by the sensing element. An example of sizing for a mirror M2 of 300 mm is a ring of 10mm to 20mm is typically an outside diameter Dext of the order respectively of Dint + 5% to Dint + 15%.

Le chemin optique suivi par les rayons émis par la source S est : S / M2 / M1 / élément 10 / M1 / M2 / S.The optical path followed by the rays emitted by the source S is: S / M2 / M1 / element 10 / M1 / M2 / S.

L'inclinaison de l'élément réfléchissant est variable suivant la position relative de la source S et du capteur C de part et d'autre de l'axe optique z. Pour un télescope de 1 ° de champ, elle peut varier de 0 ° à 1 °.The inclination of the reflecting element is variable according to the relative position of the source S and the sensor C on either side of the optical axis z. For a telescope of 1 ° field, it can vary from 0 ° to 1 °.

Un avantage du premier mode de réalisation dans lequel l'élément 10 est disposé autour de M2 consiste dans le fait qu'il est apte à faire partie intégrante du miroir M2. Un autre avantage consiste en ce que l'élément 10 est stable, peu influencé par l'évolution du flux thermique interne à la cavité formée par M1/M2.An advantage of the first embodiment in which the element 10 is arranged around M2 consists in the fact that it is able to be an integral part of the mirror M2. Another advantage is that the element 10 is stable, little influenced by the evolution of the internal heat flow to the cavity formed by M1 / M2.

Un deuxième mode de réalisation préféré illustré figure 8 comprend un élément réfléchissant 10, disposé à une distance proche de l'élément 10 du premier miroir M1 afin de minimiser l'effet de diminution du diamètre utile de la pupille d'entrée du télescope.
Les rayons 81, 82 issus de la source S se réfléchissent sur M2, puis sur M1, puis sur l'élément 10 disposé en amont de M1. Le chemin optique suivi par les rayons émis par la source S est S / M2 / M1 / élément 10 M1 / M2 / S. Selon ce mode de réalisation, l'élément 10 obture les rayons 83, 84 les plus périphériques incidents sur M1 et issus de la scène.
Les rayons issus de la scène observée effectuent le chemin optique :

  • Infini / M1 / M2 / D.
L'inclinaison de l'élément 10 annulaire dépend de la position relative de la source S et du capteur C de part et d'autre de l'axe optique. Par exemple, pour un télescope de 1 ° de champ, l'inclinaison est inférieure ou égale à 1 °. Préférentiellement dans ce mode de réalisation l'élément annulaire 10 a un grand diamètre Dext sensiblement égal au diamètre du miroir M1 D(M1). Préférentiellement le diamètre interne Dint de la couronne est minimisé pour réduire l'impact sur le diamètre utile du télescope. En outre, plus la largeur de l'anneau est faible, plus la tache de contrôle est résolue, mais moins il ya de flux reçu par l'élément de détection. Un exemple de dimensionnement pour un miroir M1 de 3000mm de diamètre est un anneau de 10 mm à 40 mm d'épaisseur.A second preferred embodiment illustrated figure 8 comprises a reflecting element 10 disposed at a distance close to the element 10 of the first mirror M1 in order to minimize the effect of decreasing the useful diameter of the entrance pupil of the telescope.
The rays 81, 82 from the source S are reflected on M2, then on M1, then on the element 10 disposed upstream of M1. The optical path followed by the rays emitted by the source S is S / M2 / M1 / element M1 / M2 / S. According to this embodiment, the element 10 closes the rays 83, 84 the most peripheral devices incident on M1 and from the scene.
The rays from the observed scene perform the optical path:
  • Infinity / M1 / M2 / D.
The inclination of the annular element depends on the relative position of the source S and the sensor C on either side of the optical axis. For example, for a telescope of 1 ° field, the inclination is less than or equal to 1 °. Preferably in this embodiment the annular element 10 has a large diameter Dext substantially equal to the diameter of the mirror M1 D (M1). Preferably the internal diameter Dint of the crown is minimized to reduce the impact on the useful diameter of the telescope. In addition, the smaller the width of the ring, the more the control spot is resolved, but the less flux is received by the sensing element. An example of sizing for a mirror M1 3000mm in diameter is a ring 10 mm to 40 mm thick.

La figure 9 illustre la dépendance entre l'image réalisée par une pupille annulaire et l'image réalisée pleine pupille, pour une même optique convergente de focale f égale à 30 m. La courbe 91 correspond à la tâche de diffraction 911 obtenue à partir d'une pupille pleine de diamètre 1.5 m, et la courbe 92 correspond à la tâche de diffraction 912 correspondant à une pupille annulaire dont la largeur de l'anneau est égal à 2% du diamètre de la pupille. La largeur à mi-hauteur de la tâche d'Airy 912 (anneau) est proche de la largeur à mi-hauteur de la tâche d'Airy 911 (pleine pupille). Cette propriété des pupilles annulaires est mise à profit pour réaliser un contrôle optique fin de la déformation de la tâche afin de suivre et de corriger l'évolution de la focalisation. Selon un autre exemple, cette propriété réalise un contrôle du déplacement de la tâche afin de suivre et de corriger l'évolution de la ligne de visée. En variante les deux types d'évolution sont contrôlés simultanément.The figure 9 illustrates the dependence between the image made by an annular pupil and the image made full pupil, for the same optics convergent focal length f equal to 30 m. The curve 91 corresponds to the diffraction spot 911 obtained from a full pupil with a diameter of 1.5 m, and the curve 92 corresponds to the diffraction spot 912 corresponding to an annular pupil whose width of the ring is equal to 2 % of the pupil diameter. The mid-height width of the Airy 912 task (ring) is close to the mid-height width of the Airy 911 task (full pupil). This property of the annular pupils is used to perform a fine optical control of the deformation of the task in order to follow and correct the evolution of the focus. In another example, this property realizes a control of the displacement of the task in order to follow and correct the evolution of the line of sight. In a variant, the two types of evolution are simultaneously controlled.

De manière générale, plus l'élément réfléchissant 10 de forme annulaire est fin, plus le diamètre de la tâche d'Airy est faible, ce qui permet une meilleure sensibilité du dispositif. Cependant, un anneau fin réfléchi une plus faible quantité de flux, et la sensibilité du détecteur doit être adaptée en conséquence. Ainsi, les dimensions des diamètres intérieurs et extérieurs Dint et Dext de l'anneau 10 résultent d'un compromis entre contraintes d'encombrement, résolution souhaitée et sensibilité du détecteur.In general, the finer the annular reflective element 10, the smaller the diameter of the Airy spot, which allows a better sensitivity of the device. However, a thin ring reflects a smaller amount of flux, and the sensitivity of the detector needs to be adapted accordingly. Thus, the dimensions of the inner and outer diameters Dint and Dext of the ring 10 result from a compromise between space constraints, desired resolution and sensitivity of the detector.

Pour obtenir une image de contrôle 11 de faible dimension, la source S doit être ponctuelle ou quasi ponctuelle. Avantageusement la source comprend au moins une fibre optique, qui présente un faible encombrement et permet un grand choix de longueur d'onde d'émission. A titre d'exemple, une fibre optique présente une dimension émissive de 5 µm à 100 µm. Avantageusement, le système comprend deux fibres optiques proches l'une de l'autre de légèrement défocalisées, c'est à dire positionnées au voisinage mais pas exactement dans le plan focal Pf, une première fibre étant disposée dans un premier plan perpendiculaire à l'axe optique et une deuxième fibre dans un deuxième plan parallèle au premier plan et décalé par rapport à ce premier plan, permettant de créer deux images de contrôle défocalisées, dont l'analyse conjointe permet de déterminer un signe de l'aberration optique du système d'imagerie.To obtain a small control image 11, the source S must be point or quasi-point. Advantageously, the source comprises at least one optical fiber, which has a small footprint and allows a large choice of emission wavelength. By way of example, an optical fiber has an emissive dimension of 5 μm to 100 μm. Advantageously, the system comprises two optical fibers close to one another slightly defocused, that is to say positioned in the vicinity but not exactly in the focal plane Pf, a first fiber being disposed in a first plane perpendicular to the optical axis and a second fiber in a second plane parallel to the first plane and offset with respect to this first plane, making it possible to create two defocused control images, the joint analysis of which makes it possible to determine a sign of the optical aberration of the optical system. imaging.

Selon une variante, le système d'imagerie est en fonctionnement lorsque le contrôle de surface d'onde est opéré avec le dispositif selon l'invention. Cette variante nécessite un élément de détection C différent du détecteur image D et disposé en périphérie de celui-ci. La source ne doit pas augmenter le niveau de lumière parasite dans le système optique d'imagerie 101. Avantageusement le système d'imagerie 101 fonctionne pour les longueurs d'onde dans la lumière visible et la source S émet dans les longueurs d'onde différentes, auxquelles le détecteur D est moins sensible, pour minimiser la lumière parasite introduite dans le système 101.According to one variant, the imaging system is in operation when the wave surface control is operated with the device according to the invention. This variant requires a detection element C different from the image detector D and disposed at the periphery thereof. The source must not increase the level of stray light in the optical imaging system 101. Advantageously, the imaging system 101 operates for the wavelengths in the visible light and the source S emits in the different wavelengths. , to which the detector D is less sensitive, to minimize the stray light introduced into the system 101.

Selon une autre variante, l'observation réalisée par le système d'imagerie 101 est arrêtée pendant que le contrôle de la surface d'onde est opéré par le dispositif selon l'invention. Cette variante est compatible avec un élément de détection confondu avec un des détecteur images D.According to another variant, the observation made by the imaging system 101 is stopped while the control of the wave surface is operated by the device according to the invention. This variant is compatible with a detection element merged with one of the image detector D.

Le capteur C doit être capable de détecter la répartition lumineuse de l'image de contrôle 11. Le capteur C peut être un détecteur matriciel, un détecteur quatre cadrans, un capteur linéaire, un capteur par diversité de phase.
Le type de capteur dépend du type de défaut que l'on souhaite contrôler.The sensor C must be able to detect the light distribution of the control image 11. The sensor C may be a matrix detector, a four-dial detector, a linear sensor, a phase diversity sensor.
The type of sensor depends on the type of fault you want to control.

Une méthode de contrôle est fondée sur une comparaison entre une première mesure de l'image de contrôle 11 dénommée mesure de calibration, effectuée lorsque le système d'imagerie 101 présente une qualité optique déterminée et jugée satisfaisante, et au moins une deuxième mesure de l'image de contrôle 11 réalisée après une période de fonctionnement du système.
En variante, le système est en fonctionnement lorsque la deuxième mesure est réalisée. Selon une autre variante le système est momentanément arrêté lorsque la deuxième mesure est réalisée.A control method is based on a comparison between a first measurement of the control image 11 called calibration measurement, performed when the imaging system 101 has a determined optical quality and found satisfactory, and at least a second measurement of the control image 11 made after a period of operation of the system.
Alternatively, the system is in operation when the second measurement is performed. According to another variant, the system is momentarily stopped when the second measurement is made.

Un premier exemple de type de défaut contrôlable par le dispositif selon l'invention est un défaut de surface d'onde tel une défocalisation. A partir d'une mesure de la variation de la dimension de l'image de contrôle on en déduit l'existence de défaut à l'origine de la détérioration de la qualité de la surface d'onde. A titre d'exemple un défaut de défocalisation peut être détecté à partir des première et deuxième mesures.A first example of a type of defect controllable by the device according to the invention is a wave surface defect such as a defocusing. From a measurement of the variation of the dimension of the control image one deduces the existence of defect at the origin of the deterioration of the quality of the wave surface. For example, a defocus defect can be detected from the first and second measurements.

Un deuxième exemple de type de défaut contrôlable par le dispositif selon l'invention est un désalignement de l'axe de visée, qui induit un déplacement de la position de l'image de contrôle 11 dans le plan focal Pf. A partir d'une mesure du déplacement de l'image de contrôle 11 on en déduit l'existence d'un défaut d'alignement. A titre d'exemple un désalignement peut être détecté à partir d'une première mesure correspondant au système d'imagerie 101 aligné et une deuxième mesure correspondant au système d'imagerie présentant un désalignement de l'axe de visée. Une mesure de déplacement de la position de l'image de contrôle est compatible avec l'utilisation d'un détecteur quatre cadran comme élément de détection C.A second example of a type of defect controllable by the device according to the invention is a misalignment of the line of sight, which induces a displacement of the position of the control image 11 in the focal plane Pf. measurement of the displacement of the control image 11 it is deduced the existence of a misalignment. For example, a misalignment can be detected from a first measurement corresponding to the aligned imaging system 101 and a second measurement corresponding to the imaging system having misalignment of the line of sight. A displacement measurement of the position of the control image is compatible with the use of a four-dial detector as a detection element C.

Selon un autre aspect de l'invention, il est également proposé un système optique d'imagerie 101 comprenant un dispositif de contrôle optique tel que décrit précédemment.
Le système optique d'imagerie 101 est par exemple un télescope haute résolution d'observation de la terre (résolution sol 20 à 50 cm) embarqué sur un satellite. Un exemple d'arrangement du plan focal Pf d'un tel système 101 comprenant un dispositif selon l'invention est représenté sur la figure 10. Le détecteur image D est composé d'une pluralité de capteurs linéaires ou matriciels D1, D2 etc... Par exemple une rétine composée de 5 capteurs linéaires de 6000 points de 13 µm de pas présente une longueur L d'environ 500 mm pour une hauteur h d'environ 50 mm.
Le défilement de la scène s'opère selon l'axe x. La source S et l'élément de détection C du dispositif 1 selon l'invention sont disposés de part et d'autre de l'axe optique z dans le plan focal Pf comme représenté sur la figure 10.According to another aspect of the invention, there is also provided an optical imaging system 101 comprising an optical control device as described above.
The optical imaging system 101 is for example a high resolution earth observation telescope (ground resolution 20 to 50 cm) embedded on a satellite. An example of arrangement of the focal plane Pf of such a system 101 comprising a device according to the invention is represented on the figure 10 . The image detector D is composed of a plurality of linear or matrix sensors D1, D2, etc. For example, a retina composed of 5 linear sensors of 6000 points of 13 μm of pitch has a length L of approximately 500 mm for a height h of about 50 mm.
The scrolling of the scene takes place along the x axis. The source S and the detection element C of the device 1 according to the invention are arranged on either side of the optical axis z in the focal plane Pf as shown in FIG. figure 10 .

Avantageusement, le système d'imagerie 110 représenté sur la figure 11 est actif et comprend en outre des moyens de commande 111 aptes à commander un actuateur 112 apte à effectuer une modification du système optique d'imagerie 110 de manière à corriger au moins partiellement le défaut identifié par l'analyse d'une ou plusieurs images de contrôle.Advantageously, the imaging system 110 represented on the figure 11 is active and further comprises control means 111 able to control an actuator 112 able to effect a modification of the optical imaging system 110 so as to at least partially correct the defect identified by the analysis of one or more images of control.

A titre d'exemple sur la figure 11 est représenté un système d'imagerie actif 110 comprenant un premier miroir M1 et un deuxième miroir M2 tel que décrit précédemment. Le type de défaut mesuré comprend une défocalisation et l'actuateur 112 est apte à commander un déplacement d'un élément optique, par exemple le deuxième miroir M2, de manière à corriger la défocalisation.
Le processus peut s'opérer de manière itérative selon une boucle, en effectuant pour chaque déplacement de l'actuateur une mesure de l'image de contrôle 11 jusqu'à ce que l'image de contrôle atteigne une dimension prédéterminée ou soit de dimension similaire à une l'image de calibration précédemment enregistrée.As an example on the figure 11 is shown an active imaging system 110 comprising a first mirror M1 and a second mirror M2 as described above. The type of defect measured includes a defocusing and the actuator 112 is able to control a displacement of an optical element, for example the second mirror M2, so as to correct the defocusing.
The process may be iteratively performed in a loop, performing for each actuator displacement a measurement of the control image 11 until the control image reaches a predetermined size or is of similar size to a previously saved calibration image.

Avantageusement, le système d'imagerie 120 représenté sur la figure 12 est actif et le défaut détecté par le dispositif selon l'invention comprend un désalignement de l'axe de visée par exemple en utilisant un élément de détection C tel un détecteur quatre cadrans. L'évolution de l'axe de visée se traduit par un décentrage de la l'image de contrôle reçue par le détecteur C. Les moyens d'analyse couplés à l'élément de détection identifient l'amplitude et le sens du déplacement. Le système d'imagerie 120 comprend en outre des moyens de commande 113 aptes à commander un actuateur de type miroir Mtt mobile en rotation ou miroir Tip-Tilt selon l'acronyme anglo saxon, de manière à modifier angulairement l'axe de visée afin de corriger le désalignement. Le miroir Mtt mobile est disposé préférentiellement sur la pupille de sortie du système d'imagerie.
Le processus peut s'opérer de manière itérative selon une boucle, en effectuant pour chaque déplacement du miroir Mtt une mesure du centrage de l'image de contrôle 11 jusqu'à ce que l'image de contrôle soit centrée. La bande passante de la boucle d'asservissement est à adapter à la fréquence de la perturbation que l'on souhaite corriger.Advantageously, the imaging system 120 represented on the figure 12 is active and the defect detected by the device according to the invention comprises a misalignment of the line of sight for example by using a detection element C such a detector four dials. The evolution of the line of sight results in a decentering of the control image received by the detector C. The analysis means coupled to the detection element identify the amplitude and the direction of the displacement. The imaging system 120 furthermore comprises control means 113 able to control a mirror-type mirror rotation actuator Mtt or Tip-Tilt mirror according to the Anglo-Saxon acronym, so as to angularly modify the line of sight in order to correct the misalignment. The mobile mirror Mtt is preferably placed on the exit pupil of the imaging system.
The process may operate iteratively in a loop, performing for each movement of the mirror Mtt a measurement of the centering of the control image 11 until the control image is centered. The bandwidth of the servo loop is to be adapted to the frequency of the disturbance that is to be corrected.

En variante, les deux types de boucles sont implémentés dans le système optique d'imagerie actif et le défaut comprend une défocalisation et un désalignement de la ligne de visée. Selon un mode de réalisation, la source S et le capteur C sont communs aux deux boucles.Alternatively, both types of loops are implemented in the active imaging optical system and the defect includes defocusing and misalignment of the line of sight. According to one embodiment, the source S and the sensor C are common to both loops.

Selon un autre mode de réalisation, le système comprend deux capteurs C spécialisés, l'un pour le contrôle de la surface d'onde et l'autre pour le contrôle de la ligne de visée.According to another embodiment, the system comprises two specialized C sensors, one for the control of the wave surface and the other for the control of the line of sight.

Claims (16)

Dispositif de contrôle optique d'un système optique d'imagerie (101) présentant un plan focal (Pf), un axe optique (z), une pupille d'entrée, ledit système formant une image d'une scène sensiblement à l'infini sur au moins un détecteur d'image (D) disposé sensiblement dans ledit plan focal (Pf), ledit dispositif comprenant : - au moins une source (S) émettrice quasi ponctuelle disposée en périphérie dudit détecteur (D) et sensiblement dans ledit plan focal (Pf), - un élément (10) réfléchissant et de surface plane, - ledit élément (10) étant disposé en amont dudit système d'imagerie (101) en considérant le sens de propagation des rayons lumineux provenant de ladite scène, et selon une position et une inclinaison telles qu'une image de contrôle (11) de ladite source (S) réalisée par ledit système optique (101) et réfléchie par ledit élément (10) soit disposée sensiblement dans ledit plan focal (Pf) sur un élément de détection (D, C) relié à des moyens d'analyse de ladite image de contrôle (11) permettant d'identifier d'éventuels défauts optiques, - ledit élément (10) présentant une forme annulaire de manière à laisser passer des rayons lumineux issus de ladite scène et traversant ladite pupille d'entrée. Optical control device of an imaging optical system (101) having a focal plane (Pf), an optical axis (z), an entrance pupil, said system forming an image of a scene substantially at infinity on at least one image detector (D) disposed substantially in said focal plane (Pf), said device comprising: at least one quasi-point emitting source (S) disposed at the periphery of said detector (D) and substantially in said focal plane (Pf), a reflective element (10) with a flat surface, said element (10) being arranged upstream of said imaging system (101) by considering the direction of propagation of the light rays originating from said scene, and according to a position and an inclination such that a control image (11) of said source (S) produced by said optical system (101) and reflected by said element (10) is disposed substantially in said focal plane (Pf) on a detection element (D, C) connected to analysis means of said control image (11) for identifying any optical defects, - said element (10) having an annular shape so as to let light rays from said scene and passing through said entrance pupil. Dispositif de contrôle optique selon la revendication 1 dans lequel ledit élément de détection comprend un capteur (C) disposé en périphérie du détecteur image (D).An optical control device according to claim 1 wherein said sensing element comprises a sensor (C) disposed at the periphery of the image detector (D). Dispositif de contrôle optique selon la revendication 1 dans lequel ledit élément de détection comprend un desdits détecteurs d'image (D)An optical control device according to claim 1 wherein said sensing element comprises one of said image sensors (D) Dispositif selon l'une des revendications précédentes dans lequel ledit système optique (101) comprend un télescope comprenant au moins un premier miroir collecteur asphérique (M1) et un deuxième miroir (M2).Device according to one of the preceding claims wherein said optical system (101) comprises a telescope comprising at least a first aspherical collector mirror (M1) and a second mirror (M2). Dispositif selon l'une des revendications précédentes dans lequel ledit système optique (101) comprend un télescope de type « TMA ».Device according to one of the preceding claims wherein said optical system (101) comprises a telescope type "TMA". Dispositif selon les revendications 4 ou 5 dans lequel ledit élément (10) est disposé autour du deuxième miroir (M2).Device according to claims 4 or 5 wherein said element (10) is arranged around the second mirror (M2). Dispositif selon les revendications 4 ou 5 dans lequel ledit élément (10) est disposé à une distance proche du premier miroir (M1) de manière à minimiser l'effet de diminution du diamètre utile de ladite pupille d'entrée.Device according to claims 4 or 5 wherein said element (10) is disposed at a distance close to the first mirror (M1) so as to minimize the effect of decreasing the effective diameter of said entrance pupil. Dispositif selon l'une des revendications précédentes dans lequel ladite source (S) comprend une première fibre optique disposée dans un premier plan perpendiculaire à l'axe optique et une deuxième fibre optique disposée dans un deuxième plan parallèle au premier plan et décalé par rapport à ce premier plan, le premier et deuxième plan étant disposé au voisinage du plan focal (Pf), les deux images de contrôle défocalisées permettant de déterminer un signe de l'aberration optique du système d'imagerie.Device according to one of the preceding claims wherein said source (S) comprises a first optical fiber disposed in a first plane perpendicular to the optical axis and a second optical fiber disposed in a second plane parallel to the first plane and offset from this first plane, the first and second plane being disposed in the vicinity of the focal plane (Pf), the two defocused control images for determining a sign of the optical aberration of the imaging system. Dispositif selon l'une des revendications précédentes dans lequel ledit capteur (C) est un capteur par diversité de phase.Device according to one of the preceding claims wherein said sensor (C) is a phase diversity sensor. Dispositif selon l'une des revendications précédentes dans lequel ledit capteur (C) effectue une première mesure de calibration de ladite image de contrôle (11) lorsque ledit système d'imagerie (101) présente une qualité optique déterminée et au moins une deuxième mesure de ladite image de contrôle réalisée après une période de fonctionnement dudit système d'imagerie (101), lesdits moyens d'analyse étant adaptés pour identifier un défaut optique par comparaison entre lesdites première et deuxième mesure de ladite image de contrôle.Device according to one of the preceding claims wherein said sensor (C) performs a first calibration measurement of said control image (11) when said imaging system (101) has a determined optical quality and at least a second measurement of said control image performed after a period of operation of said imaging system (101), said analyzing means being adapted to identify an optical defect by comparison between said first and second measurements of said control image. Dispositif selon l'une des revendications précédentes dans lequel ledit dispositif est adapté pour identifier une défocalisation dudit système d'imagerie (101).Device according to one of the preceding claims wherein said device is adapted to identify a defocusing of said imaging system (101). Dispositif selon l'une des revendications précédentes dans lequel ledit dispositif est adapté pour identifier un désalignement d'un axe de visée dudit système d'imagerie (101).Device according to one of the preceding claims wherein said device is adapted to identify a misalignment of a line of sight of said imaging system (101). Système optique d'imagerie (101) comprenant un dispositif de contrôle optique selon l'une des revendications précédentes.An optical imaging system (101) comprising an optical control device according to one of the preceding claims. Système optique d'imagerie actif (110) selon la revendication 13 comprenant en outre des moyens de commande (111,113) aptes à commander un actuateur (112, Mtt) apte à effectuer une modification dudit système optique d'imagerie (110) de manière à corriger au moins partiellement ledit défaut.Active imaging optical system (110) according to claim 13 further comprising control means (111, 113) adapted to control an actuator (112, Mtt) adapted to effect a modification of said imaging optical system (110) so as to at least partially correcting said defect. Système optique actif selon la revendication 14 dans lequel ledit défaut comprend une défocalisation et ledit actuateur (112) est apte à commander un déplacement d'un élément optique (M2) de manière à corriger ladite défocalisation.Active optical system according to claim 14 wherein said defect comprises a defocusing and said actuator (112) is adapted to control a displacement of an optical element (M2) so as to correct said defocusing. Système optique actif selon la revendication 14 dans lequel ledit défaut comprend un désalignement d'un axe de visée et comprenant en outre des moyens de commande (113) aptes à commander un actuateur de type miroir (Mtt) mobile en rotation de manière à modifier angulairement l'axe de visée afin de corriger le désalignement.Active optical system according to claim 14 wherein said defect comprises a misalignment of a sighting axis and further comprising control means (113) able to control a mirror-type actuator (Mtt) rotatable so as to modify angularly the line of sight to correct the misalignment.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015040117A1 (en) * 2013-09-20 2015-03-26 Thales Telescope comprising inner adjustment means in the focal plane

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9720223B2 (en) * 2013-03-15 2017-08-01 Lawrence Livermore National Security, Llc Integrated telescope assembly
CN104333753B (en) * 2014-11-25 2017-04-05 广东威创视讯科技股份有限公司 The color monitoring device of optical projection system and system
US10935780B2 (en) 2018-10-04 2021-03-02 Lawrence Livermore National Security, Llc Integrated telescope for imaging applications
CN112285943B (en) * 2020-10-29 2022-10-25 中国航空工业集团公司洛阳电光设备研究所 Shaft penetrating assembling and adjusting method and assembling and adjusting equipment for clamping type telescopic system and transmission system
KR102539396B1 (en) * 2021-11-25 2023-06-02 주식회사 팩트론 Apparatus and method of carrying and installing having shaft alignment function
CN116222969A (en) * 2022-12-30 2023-06-06 中国科学院长春光学精密机械与物理研究所 Dynamic line frequency matching simulation device in TDI CCD large attitude angle push broom imaging process

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3942894A (en) * 1974-11-20 1976-03-09 The United States Of America As Represented By The Secretary Of The Air Force Self referencing retransmitting alignment sensor for a collimated light beam
US20060098276A1 (en) * 2004-11-08 2006-05-11 Agency For Defense Development Large telescopic optical system with null alignment optics

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3518005A (en) * 1967-01-04 1970-06-30 Us Army Optical boresight device
US4155096A (en) * 1977-03-22 1979-05-15 Martin Marietta Corporation Automatic laser boresighting
US4385834A (en) * 1980-07-28 1983-05-31 Westinghouse Electric Corp. Laser beam boresight system
US4772122A (en) * 1986-08-18 1988-09-20 Westinghouse Electric Corp. Alignment technique for laser beam optics
US5142400A (en) * 1989-12-26 1992-08-25 Cubic Corporation Method and apparatus for automatic acquisition and alignment of an optical beam communication link
US5880834A (en) * 1996-10-16 1999-03-09 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Convex diffraction grating imaging spectrometer
US6100974A (en) * 1998-09-15 2000-08-08 California Institute Of Technology Imaging spectrometer/camera having convex grating
US6522440B1 (en) * 1999-04-28 2003-02-18 Trw Inc. Inter-satellite optical link track sensor
JP4248220B2 (en) * 2002-10-21 2009-04-02 三菱電機株式会社 Reflective optics
GB0314444D0 (en) * 2003-06-20 2003-07-23 Univ Heriot Watt Novel wavefront sensor
US7184136B2 (en) * 2004-04-27 2007-02-27 Santa Barbara Infrared, Inc. Optical alignment method and system
JP4694331B2 (en) * 2005-09-27 2011-06-08 Ｈｏｙａ株式会社 Optical system for adjusting the tilt of the objective lens
GB0715438D0 (en) * 2007-08-09 2007-09-19 Stfc Science & Technology Optical mirror system
FR2936893B1 (en) * 2008-10-06 2010-11-19 Astrium Sas OPTICAL TRANSMIT RECEIVING ASSEMBLY WITH CONTROL OF TRANSMISSION DIRECTION
US7944559B2 (en) * 2009-03-17 2011-05-17 Bae Systems Information And Electronic Systems Integration Inc. Airborne hyperspectral imaging system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3942894A (en) * 1974-11-20 1976-03-09 The United States Of America As Represented By The Secretary Of The Air Force Self referencing retransmitting alignment sensor for a collimated light beam
US20060098276A1 (en) * 2004-11-08 2006-05-11 Agency For Defense Development Large telescopic optical system with null alignment optics

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015040117A1 (en) * 2013-09-20 2015-03-26 Thales Telescope comprising inner adjustment means in the focal plane

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US9232214B2 (en) 2016-01-05
JP6262537B2 (en) 2018-01-17
KR20140091491A (en) 2014-07-21
EP2755072B1 (en) 2015-07-29
CA2838603A1 (en) 2014-07-11
US20140198222A1 (en) 2014-07-17
FR3001049B1 (en) 2015-02-06
KR102052757B1 (en) 2019-12-05
JP2014134802A (en) 2014-07-24
FR3001049A1 (en) 2014-07-18

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